Devices are used for measuring buildings, ground structures, machines and plants etc. In general, these systems comprise a measuring head wherein a measuring beam is deviated at a high speed and in a fan-like manner. Deviation of the measuring beam can be achieved by pivoting mirrors, rotating mirror wheels or the like. Often it is desired to measure inner rooms of buildings, caverns, and caves, when excavating tunnels or mines etc. Applications under especially difficult conditions are in steel industry when measuring converters and transport vessels or containers for molten pig iron or steel.
For operational reasons, molten metals are often transported from a place of production to a processing place. In steel industry, appropriate vessels, so-called torpedo ladles, are used to bring liquid pig iron from a blast furnace to a converter and, optionally, from it to a foundry, particularly to continuous casting machines, where slabs are cast as a starting material for mill processing. These torpedo ladles, which are able to contain several hundred of tons of iron melt or steel melt, have a lining which constitutes a thermal isolation and, at the same time, protects the steel jacket of the vessel against the action of the melt. As in steel converters, linings of such torpedo ladles are subjected to wear, and the result can be, in particular, that individual bricks of the lining break out. Since such damage can seriously affect the security and the environment, the lining of this transport equipment has to be inspected, repaired or replaced on a regular basis which, of course, causes high expenses. When carrying out such an inspection, the torpedo ladle (or any other vessel for materials) has to be cooled down and, afterwards, has to be heated slowly up to working temperature. This results in a considerable interruption of operation that causes correspondingly high costs.